hi, i am workin on my 89 iroc 350 with no mods that i know of.

it starts hard and seems to run extreemly rich. i have white exhaust and an unburt fuel smell.

i did a full tuneup and set the timing. when i started messin the timing it was set very advanced like around 20 and i brought it down to about 9 and it started running and starting better. i checked the code and got a whole buch of them so i reset the computer and went for a drive, the only code i got back was code 42 (est?) and the book i have doesnt really tell me what that all entails.

so my question is what does 42 all entail and what should base timing be for this car, i have foud a few different suggestions on the base point but my car is missing its sticker and id like to take every thing back to base so i can get it to where i want in the future

thanks for any help

 

If your burning some smoke you are burning some coolant somewhere. I would think it may be a head gasket causing your headaches. Water don't like being compressed....

Code 42 shows up as electonic spark timing. Check either the ignition module or try another HEI module. Hope it helps.

 

hi, i am workin on my 89 iroc 350 with no mods that i know of.

it starts hard and seems to run extreemly rich. i have white exhaust and an unburt fuel smell.

i did a full tuneup and set the timing. when i started messin the timing it was set very advanced like around 20 and i brought it down to about 9 and it started running and starting better. i checked the code and got a whole buch of them so i reset the computer and went for a drive, the only code i got back was code 42 (est?) and the book i have doesnt really tell me what that all entails.

so my question is what does 42 all entail and what should base timing be for this car, i have foud a few different suggestions on the base point but my car is missing its sticker and id like to take every thing back to base so i can get it to where i want in the future

thanks for any help

 

Since code 42 is an est code. Id check to make sure all the wires that involve timing are good, check the ignition control module...that could deff be why the car runs like crap. Also take a look at the knock sensor and your distributor in general.
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set base timing to 6 with the est connector unplugged...and when you plug it back in and start the car..itll jump to 8 degrees btc

 

Code 42 = Electronic spark timing circuit (EST)
Generally the ECM has seen a short or open in the EST circuit.
Hope this helps... it's from a General motors Manual...
1.. Clear codes, Idle engine for 1 min or until SES light comes on, turn car off, turn key to "on" position, retrieve codes.
code 42?? if yes goto next step.
Ignition off, disconnect ecm connectors, turn ignition on, use ohm meter in 1000-2000 ohm range, probe ecm harness 32 pin connector (ckt 423, pin d4 white wire) with + lead of meter the other lead to ground.
less than 500 ohms? no = open wire, faulty connection or faulty ignition module (the one in the distributor)
if no goto step 2, if yes continue, probe ECM 32 pin connector (ckt 424 or d5 pin tan/blk wire) below the white wire, with a test light, light lights up, disconnect ignition module 4 way connector, light on?.. ckt maybe shorted to ground. if the light goes off... faulty Ignition module.
step 2, Test light doesn't light up, this step is tricky, more than 2 hands help With the ohm meter + lead still connected to pin d4 (white wire), and the other connected to ground, take the test light, this time connect the alligator clip to 12v,and the tip of the test light to pin d5, watch the meter carefully, the resistance should jump from 500 ohm to 5000 ohm reading or out of limits for the meters selected range.
Does it? yes = step 4, no = step 3
step 3, no, disconnect 4-way connector at ignition module and meter should show high resistance (open circuit)
does it?? yes ckt 424 faulty connection or faulty ignition module
no, ckt 423 shorted to ground, check for rubbed sires.
step 4, yes, turn key off, reconnect ecm and idle engine for 1 minute,or until SES light comes on, code 42, possible faulty ecm, if light stays off then check connections at the Ignition module and ECM, maybe open or short in the circuit.on ckt's 423, 424
hope this helps. if you have an auto parts store nearby, check and see if they can check the ignition module for you. are you setting the timing with the bypass wire disconnected? it's the tan/blk wire connector along the fire wall. I would try a base timing of 6-8 degrees, then reconnect the timing connector. White smoke = coolant; blue = oil; black = excessive fuel

 

thats much more helpful then what i said heh

 

thanks for the answers guys, i found a wire that was bad by one of the conectors and fixed it.

now ive got a couple more ??s

first what should my base timing be, and more importantly what would cause a fuel pressure regulator to go bad?

this one that just went bad is only like 100miles old probably 10hrs or so, the problem with it is that its leaking fuel out of the vacume tube that connects to the plenum, i think thats whats cousing my unburnt fuel smell and the rough runnin. would a clogged return line cause this problem and if so how would i go about checken it out and fixin it. replacin the whole thing doesnt sound like a fun project but any suggestion here would be awsome

 

Well the stock base timing with the connector unplugged should be 6 BTC

As fas as the fuel pressure regulators go, i know the diaphragm goes bad sometimes, but what causes it i dont know. Somebody else is going to have to answer that part for ya, sorry

 

Usually you get a code 42 when you unhook the est wire to set the timing. Reset the ecu and see what happens.

Edit: Didnt read too far into it to see you already did that.

 

Stock noncomputer advanced timing is 6*.. make sure you are unpluging the connection with the brown and white wires? before setting your timing....

I run mine @ 15*.....generally 8-12* works nicely.

(There should be a sticker in the front of the hood that gives you some info on the car)